distr_info: don't fill data if already overrided

bin/distr_info

@@ -926,9 +926,6 @@ print_help()
     echo "Run without args to print all information."
 }
 
-fill_distr_info
-[ -n "$DISTRIB_ID" ] || DISTRIB_ID="Generic"
-
 if [ -n "$*" ] ; then
     eval lastarg=\${$#}
     case "$lastarg" in
@@ -942,6 +939,12 @@ if [ -n "$*" ] ; then
     esac
 fi
 
+# if without override
+if [ -z "$DISTRIB_ID" ] ; then
+    fill_distr_info
+    [ -n "$DISTRIB_ID" ] || DISTRIB_ID="Generic"
+fi
+
 if [ -z "$1" ] ; then
     print_total_info
     exit